It is well known that the skin of human beings takes on a characteristic yellowish color if sufficient amounts of carotene are administered for a certain length of time. The observation was made, however, by the late A. F. Hess1 that the skin of some children who received 1 teaspoonful of carotene in oil (0.3 Gm. of carotene per hundred cubic centimeters of oil) for twelve months started to lose its yellowish tinge in spite of the fact that the same amount of carotene was still being given. This phenomenon was witnessed by Hess in six subjects.

EXPLANATION OF DECOLORATION PHENOMENONIn the first of the studies presented here I attempted to find an explanation of this decoloration. Studies were made on five of the children in whom Hess had observed decoloration.2Two possible explanations had to be considered: (1) an increased rate of destruction of carotene in